Pump



E. C. DUDLEY Feb. 2, 1960 PUMP 4 Slfnaets-Sheerl 1 Filed March 17. 1954 www. vw n mw mw n ww umm, Nw

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PUMP

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PUMP

Filed March 1'?. 1954 4 Sheets-Sheet 3 LL] vn/vw .gig/E. y

nited States Patent PUlVIP Edward C. Dudley, Burbank, Calif., assigner to Thompson Ramo Wooldridge Inc., Cleveland, Ohio, a corporation of Ohio Application March 17, 1954, Serial No. 416,793

9 Claims. (Cl. 1031-42) This invention relates to a pump of the angular piston and cylinder type adapted to be driven throughout a very wide range of speeds and still deliver a substantially constant flow at a predetermined pressure. Specifically, this invention relates to an angular piston and cylinder block pump having a combined ow valve and orifice arrangement for controlling the positions of the cylinder blocks relative to their end plates to reduce pump noise and to join the inlet and outlet ports of the pump whereby the pump will quickly deliver a substantially constant flow of uid throughout a wide range of operating speeds.

.Patented Feb. 2, 1960 mfice to protect the pump and other parts in the hydraulic In my co-pending application, Serial No. 174,611,

tiled July 19, 1950, now Patent No. 2,779,296, there is disclosed and claimed a hydraulic pump or motor of the angular piston and cylinder type having the cylinder blocks thereof urged against ported end walls of the pump casing to seal the inlet and outlet ports from each other. Fluid under pressure developed by the pump leaks into the space between the cylinder blocks for acting on the inner faces of the blocks to urge the blocks against the end faces of the casing. Portions of the outerV faces of the blocks are vented to the pump inlet to reduce the area subjected to pressure and thereby provide a larger elective area on the inner faces for developing load or pressure between the sealing faces of the blocks and the casing.

It has now been found that high speed operation of the pump disclosed in my aforesaid application may develop pressures between the cylinder blocks to such an extent as to urge the blocks too tightly against the end walls of the pump thereby creating excess wear and producing undesired noise. In installations where the pump must be subjected to wide variations in speed ranges such as for example, in automotive power steering installations where the pump is driven by the automobile engine, the speed ratio may vary throughout such a wide range so as to create unnecessary pump Wear. In such installations, the power steering apparatus requires sufficient lluid liow at suicient pressure even at idling engine speeds and does not require any more than this minimum ow even at the highest engine speeds. Bypassing of the excess pumped uid is not a satisfactory solution because this creates excessive heat and consumes power which is not used. f

The present invention now eliminates the heretofore wasted power and prevents excessive heat development by venting the space between the cylinder blocks to a flow control valve in the discharge line of the pump. This valve carries an orice to create the desired pressure differential and whenever this dilerential exceeds the predetermined amount, the space between the cylin. der blocks is automatically vented to the pump inlet thereby permitting the cylinder blocks to be lifted off of the end faces of the pump casing and directly connecting the inlet and outlet ports of the pump whereupon the pump will deliver only the rated flow. The invention also includes avvcheck'orutopping valvel which willN ders 14 and 15.

system.

It is then an object of this invention to provide ani automatic ow control valve for angular piston and cylinder block type pumps which will regulate the positions of the cylinder blocks relative to their inlet and'V outlet ports for maintaining a predetermined delivery', rate even throughout wide variations in speed rates ofthe pump.

A further object of this invention is to provide a com# bined pressure differential creating and ow regulating; valve for angular piston and cylinder type pumps.

A still further object of this invention is to providea controlled vent for the space between the cylinderI blocks of an angular piston type pump to control the= positions of the cylinder blocks relative to the sealing; end faces of the pump housing whereby the inlet and out let ports of the pump will be communicated through passages of varying capacity for maintaining a constant Ailow rate for the pump.

A further object of the invention is to eliminate heretofore encountered noise in the operation of angular piston and cylinder block type of pumps.

A specific object of this invention is to provide an oriiced thimble valve in the discharge line of an angular piston and cylinder block type pump for venting the space between the cylinder blocks to a lesser pressure Whenever the pressure differential on opposite sides of the orifice exceeds a predetermined differential to therebyI permit the cylinder blocks to ride otf of the sealing end faces of the pump housing for connecting the inlet and outlet ports of the pump.

Other and further objects of this invention will be apparent to those skilled in the art from the following detailed description of the annexed sheets of drawingswhich, byv way of preferred example only, illustrate one embodiment of the invention.

On the drawings:

Figure 1 is a longitudinal cross-sectional view, with parts in elevation, of the angular piston and rotary cylinder block pump of this invention showing the cylinder blocks in maximum pumping position.

Figure 2 is a view similar to Figure 1 but showing the cylinder blocks in positions for joining the inlet and outlet ports of the pump to decrease the noise of operation and the pumping capacity of the pump in accordance with this invention.

Figure 3 is a transverse cross-sectional view with parts in elevation, taken along the line III-III of Figure 1.

Figure 4 is a transverse cross-sectional view with parts in elevation, taken along the line IV-IV of Figure l. Figure 5 is a perspective view of one of the cylinder blocks of the pump and illustrating several angular pistons in the block, the remaining pistons being removed.

Figure 6 is a transverse cross-sectional view taken along the line VI-VI of Figure 1.

Figure 7 is a longitudinal cross-sectional view of a modified pump arrangement according to this invention wherein the ow regulating valve is separate from the vent valve. 'y

As shown on the drawings:

As shown in Figures 1 and 2, the pump 10 of this invention includes a housing 11 having cylindrical bores 12 and 13 extending inwardly from opposite ends thereof and disposed in angular relation to dene an interior angle therebetween of more than and less than 180, preferably about The cylindrical bores 12 and 13 terminate respectively at shoulders 14 and 15 at their divergent ends and may ormay not merge at their convergent ends. A space 16is provided between the shoulreduce the pressure in the space and will permit the cylinder blocks 17 and 18 to move inwardly toward their shoulders 14 and 15. Such inward movement of the blocks will, of course,- be under the inuence of the discharge pressure acting on the outer faces 21 and 22 of the blocks and will space these outer faces from their coacting sealing faces 29 and 37. The inlet and outlet ports 30 and I33:, 38 and 39 of the pump will thereby be placed in communication and fluid will be metered therebetween. In this manner, the pump is automatically regulated to deliver only a predetermined flow rate since excess delivery will result in the shifting of the valve 54 and the lessening of the flow through the tube 55 even when the pump speeds would ordinarily call for a higher ow rate. The ball check valve 66 serves as a topping valve or safety valve in the event that the metering valve 54 does not suiiiciently cut down the pump pressure by effecting the unseating of the cylinders blocks 17 and 18.

In the modified pump 70 of Figure 7, parts identical with parts of the pump 10 have been marked with the same reference numerals. As therein shown, the depending boss 11a of the casing 11 has Ia second bore 71 therethrough above the bore 53 and the tube 55 has a branch 72 connected to one end of this bore 71 While the other end is closed by`a vented plug 73. A solid cylindrical valve 74 is slidable in the bore 71` and has a groove 75 therearound for lregistering with the passage 52. This passage 52 instead of continuing to the bore 53 as in the pump 10, extends `to a passage 76 opening to the atmosphere or pump inlet. A spring 77 urges the valve 74 to move the groove 75 lthereof out of registration with the passage 2 until pump pressure in the tube 72 is high enough to Aact on the solid end face of the valve 74 for shifting the valve against the spring bias whereupon the space 16 will be vented to the passage 76.

The valve 54 in the bore 53 when shifted by an increased pressure drop across its orifice 59 due to increased flow will uncover a vent passage 7S to relieve excess flow as desired.

The relief valve 66 operates in 'the same manner as in the pump 10 to protect -against excessive pressures in the tube 56.

The pump 70 thus has a separate valve 74 controlled by pump pressure upstream from the flow valve 54 and the ow valve dumps the excess uid whenever the flow rate increases beyond lthe amount desired. This arrangement responds quickly to correct excess flo-W conditions but the excess fluid is pumped before being released in the event the valve 74 is not first shifted to cause venting of the space 16 and axial shifting of the cylinder blocks 17 and 13 to decrease the pump output.

It will be understood that variations and modifications may be effected without departing from the scope of the novel concepts of this invention. l

I claim as my invention:

l. ln a hydraulic machine having a casing with communicating angularly disposed cylindrical bores, cylinders rotatable and axially shiftable in said bores, said cylinders having axially extending holes therethrough, angular pistons slidably mounted in said holes, means providing a space in said casing receiving said pistons therethrough and disposed between said cylinders, end walls in said casing receiving the outer ends of the cylinders thereagainst, said casing having an inlet and an outlet port communicating through an end Wall with the holes in the cylinders respectively along areas where the pistons are retracted from the outer ends of the cylinders and along areas where the pistons are adjacent the outer ends of the cylinders, a flow metering valve in fluid communication with said outlet port and having a fixed orifice subjected to the discharge pressure of the pump and a relief passageway in communication with the space between the cylinders in the pump casing, and means biasing the metering valve to close said relief passage way, said metering valve being shiftable whenever the pressure differential across the fixed orifice'theeof exceeds a predetermined `amount to selectively open the relief passageway whereupon the cylinder blocks 'will ride off of the end faces in the pump to meter flow between the inlet and outlet ports.

2. A hydraulic machine comprising a casing having communicating bores in angular relation, cylinder blocls rotatable and slidable in said bores, end walls on said casing adapted to receive the outer end faces of the cylinder blocks in sealing relation, said casing having a space between said cylinder blocks, said cylinder blocks having a plurality of axial holes therethrough, angled pistons having the angled legs thereof respectively slidably mounted in said holes, means for rotating said cylinder blocks to shiftthe positions of the ends of the pistons relative to the outer end faces of the blocks for effecting a pumping through said holes, said space between the cylinder blocks communicating through leakage paths with the fluid discharged from the pump, said pump having an inlet and an outlet respectively communicating with the outer end faces of the cylinder blocks along separated areas thereof where the pistons are retracted inwardly from the end faces and where the pistons are adjacent the end faces, a ow metering valve having a fixed orifice in the pump youtlet adapted to maintain a predetermined pressure differential on opposite sides thereof, said flow metering valve having a passage selectively registering With a relief passage connected to the space between the cylinder blocks whenever the pressure differential across said orifice exceeds a predetermined amount, thereby to relieve the pressure in said space between the cylinder blocks and permit the discharge pressure to move the blocks toward each other and meter flow between the -outlet and inlet of the pump.

3. A pump having a casing with interconnected bores at an angle of more than and less than 180, cylinder blocks rotatable and shiftable in said bores, stops limiting the inward shifting of the cylinder blocks in said bores to provide a space between the blocks, end heads on said pump adapted to receive the outer faces of the cylinder blocks thereagainst, said cylinder blocks having a plurality of axially extending holes therethrough, hollow angled pistons having the angled legs thereof slidably mounted in said holes and interconnecting said blocks, a drive shaft rotatably carried by one of said ends, said outer faces of the cylinder blocks being recessed inwardly from said holes, said shaft projecting into one of said recesses and being coupled with the cylinder block to drive t-he block while accommodating axial shifting of the block thereon, said end heads having arculate inlet and outlet ports respectively registering with the holes in the cylinder blocks at areas where the pistons are retracted from the end faces and at areas where the pistons are adjacent the end faces, passages in said end heads connecting the recesses in the cylinder blocks with the inlet ports thereof, one of said inlets having an inlet boss and an outlet boss respectively communicating with the inlet and outlet ports, means defining a passage in said casing connecting the space between the cylinder blocks to a lower pressure, a valve in said passage, means biasing said Valve to closed position, said valve being l exposed to a pump discharge pressure and being shiftable under the influence of such pressure against said biasing means to open the passage and communicate the space to lower pressure whenever the pump discharge pressure exceeds a predetermined maximum whereby pressure against the outer end faces of the cylinder blocks will cause the blocks to ride oi of the end heads and meter flow between the inlet and outlet ports to reduce der block type pump including a housing having end' walls with sealing faces, an inlet, an outlet and a relief passage, a pair of spaced axially boredcylinder blocks rotatably journalled in said housing and defining a space therebetween in the housing, a plurality of -angular pistons slidably mounted in said bores to provide suction at said inlet and pressure at said outlet, said sp-ace being subjected to outlet pump pressure for -urging said cylinder blocks against said sealing faces, a pressure responsive ow controlling valve positioned between said housing space and said relief passage and exposed to said outlet to selectively connect the space in the housing between the cylinder blocks with said relief passage whenever the ilow delivery of the pump exceeds a predetermined, maximum to permit the cylinder `blocks toride olf of the sealing faces.

5. In combination, an angular piston and rotary cylinder `block type pump including a pump housing having a pair of communicating angularly disposed bores, an outlet flow passage and a relief passage registering with said bores, a pair -of cylinder blocks having axial bores, said blocks being rotatably mounted and axially shiftable in said pump housing bores and defining a space therebetween subjected to pump discharge pressure, a plurality of angled pistons slidably mounted in the bores in said cylinder blocks, end plates closing the open ends of said angularly disposed bores in said pump housing to form pumping chambers for said pump, a shiftable, oriticed, flow metering valve member movably ,positioned in said outlet ow passage and subjected to pumpdischarge pressure and also intenposed in said relief passage to close said relief passage in an upstream position and open said relief passage in a downstream position, means biasing said valve upstream in said ow passage, said valve adapted to move to downstream position whenever the delivery rate of said pump exceeds a predetermined amount.

6. In combination, an angular piston and rotary `cylinder block type pump including a pump housing having a pair of communicating angularly disposed bores, an outlet flow passage and a relief passage registering with said bores, a pair of cylinder blocks having lbores therethrough, said blocks being rotatably mounted and axially shiftable in said pump housing bores and defining a space therebetween subjected to pump discharge pressure, a plurality of angled pistons slidably mounted in thebores in said cylinder blocks, end plates having inlet and outlet ports subjected to pump pressure closing the open ends of said angularly disposed bores in said pump housing, a ow regulating valve interposed in said relief passage to control flow through said relief passage and having a valve control body movably located in said outlet ow passage and adapted to move in said outlet low passage to open said val-ve in response to a predetermined maximum pump discharge ow rate and to connect said space with said relief passage Whenever the flow rate of tlhe pump reaches a predetermined maximum, thereby reducing the pressure in said space to permit the cylinder blocks to move toward each other and decrease the pumping capacity of the pump.

7. In combination, an angular piston and rotary cylinder block type pump including a pump housing having a discharge passage and a relief passage, a pair of rotatable, axially shiftable, relatively inclined cylinder blocks in said housing defining a space therebetween, a plurality of angular pistons slidably mounted in said cylinder blocks, a valve having a shiftable control body in said discharge passage exposed to discharge flow, said valve interposed in said relief passage to selectively connect the space between said cylinder blocks with said relief passage to a lower pressure whenever the ow rate of the pump reaches a predetermined maximum to move said valve control body to thereby maintain a predetermined pump flow rate, and a relief valve downstream of Vsaid ow metering valve to prevent the ldischarge pressure of said `pump from reaching a predetermined maximum.

8. In combination, a pump of the angular piston and rotary cylinder block type including a pump housing having a pair of intercommunicating angularly disposed bores, a pump discharge passage, a pump relief passage intersecting said discharge passage, a pair of rotatable axially shiftable cylinder blocks having a plurality of axial bores therethrough, said cylinder blocks defining a space therebetween subject to pump discharge pressure and connecting to said relief passage, a plurality of angular pistons in said bores, end plates having inlet and outlet ports formed therein connected to the discharge passage and closing the ends of the bores in said pump housing and receiving said cylinder blocks in rotative sealing engagement thereagainst, a ow regulating valve body slidably mounted in said pump discharge passage and having a discharge flow passage therethrough to pass discharge uid through said pump discharge passage and having a lateral relief passage to permit ilow through said pump relief passage when aligned therewith for relieving pressure in said space, and a spring urging said valve body upstream in said pump discharge passage and said valve relief passage out of alignment with said pump relief passage whereby a predetermined flow through said valve flow passage would cause alignment to relieve said space and to prevent the discharge of said pump from reaching a predetermined maximum.

9. In an angular piston and rotary cylinder block type pump including a pump housing having a pair of intercommunicating angularly disposed bores, end plates closing the bores, one of said plates having an inlet and an outlet, a discharge conduit connected to said outlet, av pair of rotatably mounted axially shiftable cylinder blocks having a plurality of axial bores therethrough riding on the end faces of said end plates and defining a space therebetween subjected to pump discharge pressure from leakage paths between said cylinder blocks and pump housing, a plurality of angled pistons in said cylinder block bores, a passage leading from said space, a pressure responsive valve in said passage and exposed to pump discharge pressure in said discharge conduit for selectively opening the passage and reducing the pressure in said space between said cylinder blocks to permit said cylinder blocks to ride oi the end faces `of said end plates to reduce the noise of said pump and limit the maximum output of said pump when the pump discharge pressure reaches a predetermined maximum pressure, and pressure relief means in said conduit operative to directly relieve pressure therefrom at a predetermined maximum pressure.

References Cited in the le of this patent UNITED STATES PATENTS 1,087,160 Eizerman Feb. 17, 1914 1,970,679 Walker et al Aug. 21, 1934 1,986,584 Koplar Jan. 1, 1935 1,996,889 Thomas Apr. 9, 1935 2,073,710 Raylield Mar. 16, 1937 2,364,301 MacNeil Dec. 5, 1944 2,437,791 Roth et al Mar. 16, 1948 2,459,786 Beaman et al. Jan. 25, 1949 2,505,191 Lauck Apr. 25, 1950 2,584,638 Staude Feb. 5, 1952 2,608,158 Beaman et al Aug. 26, 1952 2,698,579 Hammond Ian. 4, 1955 2,742,862 Banker Apr. 24, 1956 2,746,392 Klessig et al. May 22, 19,56 2,752,853 Eames July 3, 1956 2,768,582 Klessig et al. Oct. 30, ,1956 2,779,296 Dudley Ian, 29, 1957 2,800,083 Tweedale et al. July 23, 1957 

